(anatomy) Muscular valve connecting the stomach to the duodenum and regulating flow of materials out of the stomach.

(anatomy) The collective muscles used to control the flow of urine from the urinary bladder. These muscles surround the urethra, so that when they contract, the urethra is closed.

(anatomy) A muscular valve that controls the flow of digestive juices (bile and pancreatic juice) through the ampulla of Vater into the second part of the duodenum.

plural of lower esophageal sphincter

plural of upper esophageal sphincter

(anatomy) The sphincter situated at the upper part of the esophagus.

(anatomy) The sphincter situated at the lower part of the esophagus.